Screening And Research The DUOX2 Mutation In Patients With Congenital Hypothyroidism In Northwestern Region

Congenital hypothyroidism(CH)is a common endocrine disease caused by thyroid dysgenesis or thyroid dyshormonogenesis.Some studies indicated that the majority of CH due to the lack of thyroid hormone secretion was caused by genetic factors.The double oxidase 2(DUOX2)was the key gene of thyroid hormone synthesis,and its mutation had an important effect on the formation of CH.In this study,135 CH patients and 100 healthy individuals were recruited in the northwest region.The sequences of DUOX2 exons and exon-introns were sequenced by high-throughput sequencing.At the same time,the disease sites were tested by sanger screening,and the frequency was validated in 100 healthy samples.Then the function and effect of these potential pathogenic sites were analyzed by means of computational biology,and the relationship between DUOX2 mutation and CH clinical phenotype was discussed.According to the American Society of Medical Genetics and Genomics and the American Society of Molecular Pathology(ACMG/AMP)sequence variation criteria for the classification of disease grade.The results showed that 49 rare mutations and 2 functional polymorphisms were detected in 135 CH patients.Of the 49 rare mutations,35 were missense mutations,6 indel mutations,6 nonsense mutations and 2 splice mutations,11 of which were first discovered new mutations,and their frequency in healthy controls less than 1%.The prevalence of DUOX2 mutations was 60.7%(82/135)in 135 patients and four hotspots(p.R1110Q,P.1067L,p.R885Q,p.K530X)were significant differences in CH patients compared to healthy controls.The analysis of all missense and nonsense mutations by SIFT,PolyPhen-2,MutationTaster,FATHMM and M-CAP protein function prediction software and found 21 mutations could damage the function of protein;using MaxEntScan,NetGene2 and BDGP software found that the two mutations(IVS28+1G>T,IVS17+1G>T)could damage the function of the protein.The study found that there was no relationship between the type and number of DUOX2 mutations and the clinical phenotype,and the relationship was very complicated.The amino acids sequence analysis of seven species was carried out on the novel discovered suspected pathogenic sites,and the results showed that four mutations(p.D137E,p.R434_S440del,p.F591S,p.M1093V)were in the conserved region,may have an effect on protein structure and function.At the end of this study,according to the ACMG/AMP for the classification of pathogenic grade of suspected pathogenic sites,seven mutations(p.R1110Q,p.R885Q,IVS28+1G>T,p.R842X,IVS17+1G>T,p.K530X,p.Q481X))were pathogenic,9 possible likely pathogenic,33 variants of unknown significance,and 2 benign Mutation(p.10767,p.H678R).In addition,the functional polymorphic p.10767L was associated with an increased risk of CH(OR=2.2,P=0).In summary,this study screened the DUOX2 mutation with CH in Northwest China by using high-throughput sequencing technique.The relationship between the type and characteristics of DUOX2 mutations and the clinical phenotype was analyzed.It is of great theoretical value to extend the DUOX2 gene mutation spectrum and to further understand the pathogenesis of CH.